Microwave antennas play a crucial role in satellite communication and radar systems, while millimeter-wave antennas are indispensable for advancing high-speed telecommunications and radar technologies, especially with the emergence of 5G networks. This research focuses on the development and evaluation of two distinct Multiple Input Multiple Output (MIMO) antennas tailored for Ultra-Wideband (UWB) and millimeter-wave network applications using High Frequency Solution Setup (HFSS) software. The Hexagonal MIMO antenna, measuring 40 x 36 x 1.6 mm³, and the Dual Band Notched MIMO antenna, measuring 35 x 23 x 1.6 mm³, both utilize double-port MIMO technology and operate at frequencies of 7.5 GHz and 30 GHz. Performance parameters including Gain, Directivity, Radiation Efficiency, Return loss, Reflection Coefficient, and Beam Area are examined, with a comparative analysis conducted at both frequencies. The findings reveal the consistent superiority of the Dual Band Notched MIMO antenna, exhibiting higher gain and directivity across both frequencies. Specifically, at 7.5 GHz, gains of 24.97 dB and 33.17 dB, directivities of 6.05 dB and 5.10 dB, radiation efficiencies of 18.9 dB and 28.07 dB, beam areas of 4.94 sq. deg and 5.89 sq. deg, reflection coefficients below -12 dB, and return loss values exceeding 12 dB are observed for the Hexagonal and Dual Band antennas, respectively, while at 30 GHz, gains are 32.49 dB and 24.92 dB, directivities are 6.79 dB and 7.9 dB, radiation efficiencies are 16.41 dB and 24.57 dB, beam areas are 4.20 sq. deg and 3.07 sq. deg, and reflection coefficients and return loss values show similar trends for Dual Band and Hexagonal antennas, respectively. This study provides valuable insights for optimizing MIMO antenna designs to enhance performance in UWB and millimeter-wave network applications.

Millimeter-wave (mm-wave) communication stands as a vital technology for future wireless networks, necessitating efficient beamforming techniques to mitigate significant path loss and harness the extensive mm-wave spectrum. Traditional fully digital beamforming methods are often deemed unfeasible due to the substantial costs and energy requirements, which stem from the need for individual radio frequency (RF) chains for each antenna element particularly in Massive MIMO systems. Hybrid beamforming emerges as a more economical solution, reducing both hardware expenses and energy consumption by utilizing a limited number of RF chains. This paper offers an in-depth evaluation of hybrid beamforming in 5G and beyond mm-wave systems, proposing a new classification framework for various hardware configurations. The research employs a practical approach to compare different strategies, focusing on two main factors: the beam patterns produced with optimal and hybrid weights, and the resulting spectral efficiency, which is a key performance metric. The findings indicate that the beam patterns generated with both optimal and hybrid weights display comparable characteristics, especially for dominant beams. Additionally, the study shows that increasing the number of data streams leads to a significant boost in spectral efficiency, an essential element for enhancing 5G network performance. The systematic comparisons delve into the interactions and trade-offs between these design aspects, highlighting promising candidates for hybrid beamforming in the wireless communication systems of the future.

Microstrip Patch Antennas (MPAs) play a critical role in modern wireless communication systems due to their compact size, easy integration, and capability to ensure reliable communication across wide frequency ranges. This paper introduces enhanced designs of rectangular MPAs aimed at overcoming the narrow bandwidth limitation commonly found in traditional designs. Three innovative configurations are proposed: one featuring a simple rectangular slot on the ground plane, another integrating polygonal Defected Ground Structures (DGS), and a third utilizing rectangular DGS. These antennas are optimized at a frequency of 4 GHz using High Frequency Structural Simulator (HFSS) software to significantly improve antenna performance. The MPA without DGS showed a return loss of -21.124 dB at a resonant frequency of 4 GHz, with a Voltage Standing Wave Ratio(VSWR) of 4.8038 and a gain of 3.88 dBi. In contrast, the MPA with Polygonal DGS exhibited significant improvements, achieving a return loss of -26.87 dB at a resonant frequency of 4.1 GHz, along with a VSWR of 1.3721 and a gain of 4.38 dBi. Similarly, the MPA with Rectangular DGS demonstrated superior characteristics, with a return loss of -27.08 dB, resonance at 3.825 GHz, a VSWR of 1.4399, and a gain of 4.00 dBi. These results underscore the effectiveness of DGS in broadening the bandwidth and improving the performance of MPAs for applications below 6 GHz, making them highly suitable for next-generation wireless communication systems.